import numpy as np
from bokeh.layouts import layout
from bokeh.models.widgets import Div
from bokeh.plotting import figure, show
# helper function for coordinate conversion between lat/lon in decimal degrees to web mercator
def lnglat_to_meters(longitude: float, latitude: float) -> tuple[float, float]:
""" Projects the given (longitude, latitude) values into Web Mercator
coordinates (meters East of Greenwich and meters North of the Equator).
"""
origin_shift = np.pi * 6378137
easting = longitude * origin_shift / 180.0
northing = np.log(np.tan((90 + latitude) * np.pi / 360.0)) * origin_shift / np.pi
return (easting, northing)
description = Div(text="""<b><code>tile_demo.py</code></b> - Bokeh tile provider examples. Linked Pan and Zoom on all maps!""")
# Lady Bird Lake, Austin Texas
lat = 30.268801
lon = -97.763347
EN = lnglat_to_meters(lon, lat)
dE = 1000 # (m) Easting plus-and-minus from map center
dN = 1000 # (m) Northing plus-and-minus from map center
x_range = (EN[0]-dE, EN[0]+dE) # (m) Easting x_lo, x_hi
y_range = (EN[1]-dN, EN[1]+dN) # (m) Northing y_lo, y_hi
providers = [
"CartoDB Positron",
"CartoDB Positron retina",
"OpenStreetMap Mapnik",
"OpenTopoMap",
"USGS.USTopo",
"Esri World Imagery",
]
plots = []
for i, vendor_name in enumerate(providers):
plot = figure(
x_range=x_range, y_range=y_range,
x_axis_type="mercator", y_axis_type="mercator",
height=250, width=300,
title=vendor_name,
toolbar_location=None, active_scroll="wheel_zoom",
)
plot.add_tile(vendor_name)
plots.append(plot)
layout = layout([
[description],
plots[0:3],
plots[3:6],
])
show(layout)
